The level of circulating total NK cells (identified as CD16+CD56+CD3- lymphocytes) was significantly lower in prostate cancer patients before seed implantation compared to healthy controls (52.41% mean with 41.14–63.68% 95% CI and 67.82% mean with 62.02–73.62% 95% CI in patients before treatment and healthy controls, respectively). This evidence concerns the gene NCAM1 and prostate carcinoma.